Xenon - not leveling?

[Zed]

Hi Guys,

Issue with my baby is the Xenon's won't level, nearside does, offside doesn't.

For a while there was a fault logged with what appeared to be the front level sensor but nothing ever found wrong with sensor or linkage. Transpired to be the rear sensor linkage, plastic control arm completely mashed so that has all been replaced. Shortly after though, probably coincidence 8) , the offside Xenon dropped very low and didn't cycle through the program like the nearside. Suspect leveling motor right? Grabbed one of the those and all seemed to be good, err, nope. Initially it cycled (dipped then rose on Auto/Adaptive) and then just stopped on the low setting. You can see and hear the adjustment on the nearside but the offside seemed jammed and low. If you take everything apart and remove the power to the motor, reconnect, it seems OK for one to two cycles and them nothing...stuck low. I swapped the motors over and the offside one works perfectly on the nearside so it's not that. The diags now show a fault with the motor, no matter which one but always the offside. The DIS diags also show voltage changes from the front/rear leveling sensors as you jack/lower the car but they are original and on '04 but not faulty it seems.

I've seen elsewhere it could be phasing or the wiring regulator (part 3 from diagram which will be a mare to remove) for it to operate like this (one/two times), if it was wiring then not at all? Had the battery disconnected and starting to loose the rag with a motor fault which isn't but has to be a connected component and if the sensors were kaput the nearside wouldn't level?

So what do you think? It's due it's MOT so I'm trying to resolve before handing it to them, a fail for sure. One of the sensors perhaps off with voltage? Wiring? Can't be fuses or motor and the headlight unit is in good order, ball from motor properly housed in socket inside (a dab hand at getting that sucker back in now).

The sensors, is one for the left and one for the right or do they do different things, worth getting one for the front and see if that sorts it, expensive test though .

Thanks guys hopefully someone comes along with the answer and we're all good again

https://www.realoem.com/bmw/enUS/showparts?id=BT51-EUR---E85-BMW-Z4 3.0i&diagId=63_0758

 

[rally-chris]

The two level sensors (front and rear) are used to set the level on both headlights equally, so your problem is definitely at the headlight end of the electrical system.

Is there a lot of mechanical resistance to the inner light moving freely in the dodgy light?
Are the electrical connectors and immediate wiring in good condition?

If the motor itself is known to be good, then it sounds like the motor is drawing too much current and the control unit is therefore shutting down efforts to operate it. Too much current could be resistance to the light mechanism moving or a loss of voltage due to corroded electrical connections somewhere in the system.

Chris

 

[Zed]

Hi Chris,

Thanks for clearing that up I'd heard one was leveling and the other some sort or potentiometer...which having googled is the same thing (mechanically), doh!

I had the motor sitting freely disconnected from the headlight and the behavior was same, one/two goes and then nothing so probably counts out mechanical resistance.

So you think wiring then, where do I start? Can only really suspect the wiring regulator to the motor itself, visually it looks clean and dry / no corrosion, does it actually regulate or simply a connection plug? Else it's out with a meter and figure something out?

Cheers,
-Chris.

 

[Zed]

Are there any other control units involved? Light switch is the only one along with the load sensors? If there's others then that would be another place to look I guess but again, nothing in diags. Only had this fault since fixing the rear sensor linkage but can see that throwing anything and they may have stopped leveling in the summer without me knowing and less headlight operation. It was the visible low driving side position that alerted me to this